Carbon-contact-resistance switch



(No Model.)

F; (-1-. H. MEYER. CARBON CONTACT RESISTANCE SWITCH.

No. 549,456. Patented 110mg, 1895.

ANDREW IGRMAMT NDYOJQTHQWASNINGTON. |7.C.

' UNITED STATES PATENT OFFICE.

FRIEDRICH GUSTAV IIERMANN MEYER, OF OHARLO'FENBURG, GERMANY,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE SIEMENS & IIALSKE ELEC- TRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS.

CARBON-CONTACT-RESISTANCE SWITCH.

SPECIFICATION forming part of Letters Patent No. 549,456, dated November 5, 1895. Application filed April 4, 1894- Serial No. 506,258. (No model.)

To aZZ whom it may concern:

Be it known that I, FRIEDRICH GUSTAV HER- I MANN MEYER, a subject of the Emperor of Germany, residing at Oharlottenburg, Germany, have invented new and useful Improvements in Carbon-Oontact-Resistance Switches, of which the following is a specification.

This invention relates to a carbon-contact- 1o resistance switch; and it has for its main object the provision of means for switching an electromotor gradually into or out of circuit without producing sparks in any metallic portion of the circuit, said means consisting of pairs of carbon contacts in every part of the working circuit where a contact is made or broken.

Another object of the invention is to provide means for automatically choking or prevent 2o ing movement of the switch-lever when a normal current amperage in the line is exceeded.

In carrying out my invention I provide, in connection with a rheostat adapted to take the full line current, but subdivided so as to gradually cut the motor in or out, a series of pairs of carbon rods corresponding to the subdivisions of the rheostat, and with which contact-rods circuit is made or broken in switching in or out the several subdivisions 0 of the rheostat. These carbon contacts are connected with the switch-lever and so adjusted that when the switch-lever is actuated the several contacts are made or broken in succession in accordance with the switching 3 5 in or out of the motor. Means are also provided for compensating for wear of the carbon contacts, due to any sparking that may occur thereat.

The automatic regulating device provided in connection with the switch-lever for preventing the passage of too heavy a current upon the line consists of an electromagnet connected in circuit and a pawl upon the switch-lever acting as the armature of said 4 5 electromagnet and having a retracting spring,

the tension of which is regulated to correspond to a certain amperage in the line, the force of said spring being overcome and the pawl attracted upon the passage of an abnormal current, whereby said pawl is engaged by or against a toothed segment and movement of the lever prevented.

In the accompanying drawings, I have shown a carbon-contact-resistance switch and regulating device constructed in accordance with my invention, in Which Figure 1 is a theoretical diagram of my improved switch in connection with an electromotor and a rheostat. 2 is a rear elevation of the switch mechanism. Fig. 3 is an edge elevation thereof, and Fig. 4 is a front elevation of the same.

1 represents a standard or support of any suitable construction. To the front end of the standard is pivoted a switch-lever 2, of the usual construction, spanning a series of contact-rings 3 4 5. The shaft upon which said lever is secured extends in a journal 6 through the frame 1, and secured to the rear end of the shaft is a transverse arm 7. 00-

.operating with said arm is a second arm 8,

similar thereto, but not connected therewith. This arm 8 is secured to the lower end of a connecting-frame 0, the long upright arm of which is provided at its lower end with a slot 7 5 9, in which the shaft 2 of the lever 2 works, said frame being adapted to move up and down upon said shaft within the slot 9 as a guideway when the arm 8 is depressed by the arm 7 upon the turning of the lever 2.

The frame as a whole is substantially I- shaped, and the upper portion thereof carries a series of carbons 1O 11 12 13, secured therein in the following manner: Each rod is provided with a clamp or holder l0 to 13. A series of thumb-screws 10 to 13 are loosely secured in the upper part of the I-frame at E) and rigidly but adjustably secured at their lower ends to said clamps or holders, thus allowing the holders to move in a vertical direction with respect to the frame. A second series of regulable thumb screws or bolts lO to 13are screwed rigidly to the holders or clamps and have a free vertical 'recip rocating or sliding movement through openings in the upper part 9 of the frame; Oom-' pression-springs 10 to 13 are coiled upon said thumb screws or bolts. Arms 14 depend from the frame 9 and engage with guideways 15, so as to insure an absolutely verti- 10o creasing distances apart.

cal movement of the frame at all times and prevent sidewise movement or wabbling. A compression-spring 16, which may be either coil, loop, orelliptical, or of any other wellknown form, tends to press the lower arm 8 of the I-frame back to a normal position when released by the lever 2.

Secured to the front of the standard 1 is a rack-segment 17. This rack is adapted to engage pawl 18, secured to an auxiliary lever arm 19, pivoted to the main lever 2 in the usual manner. A spring 20, of any desired construction and adjusted to balance a determined amperage 011 the line, is secured to the lever-arm connected with said pawl in such a manner that the pawl is held from engagement with the rack until the determined amperage is exceeded, when the force of the spring will be overcome and the pawl attracted by the electromagnet 21, of which said pawl forms the armature.

The operation of my invention will irowbe described more particularly with refere-i-ice to Fig. 1. Let 22 represent the armature of the electromotor, 23 the field thereof, and'2 i 'a rheostat composed of a number of separable elements. 10 to 13 represent the lower stationary carbons of the carbon switch. The carbons 10 and 10, as will be seen from the drawings, are arranged closelytoge'ther, while the others are arranged at progressively-in- The switch-lever 2 is normally in a vertical position, as shown in Fig. 2, when the circuit is interrupted. \Vhen it is desired to put the motor 22 in circuit, the lever is turned to the right or left, according to the direction inwhich it is de sired that the armature of the motor shall rotate, and by said movement the carbons 10 and 10 of the first pair are brought into c011- tact just after the actual closing'of the circuit through the contact-rings, thus preventing any sparkingat that point. Simultaneously with the closing of the circuit through this first pair of carbons the full resistance of the rheostat 24: is put into circuit, and this resistance is of such capacity as to take the full current from the line. By continuing the turning of the lever-arm 2 either'to the right or left, as the case may be, thesuccessive pairs of carbons are brought into circuit step by step and a portion of the resistance of the rheostat cut out at each successive making of the'circuit through a new pair of contacts. This will be evident, as it will be seen from the drawings, Fig. 1, that the pairs of carbons are connected successively to the circuit through the carbons 13 and 13, when choked against the rack-segn'icnt 17.

the current from the line will flow directly through the conductors 25 instead of through the circuit of the rheostat.

By mounting the carbons of the upper series resiliently and adjustably in the frame they will in practice adjust themselves automatically for the wear imposed upon them by disintegration, due to sparking at the point of contact, as each carbon is independently supported and is capable of a considerable vertical movement, due to the action of its expanding and retruding spring, so that any inequalities will be compensated for solely by the movement of the lever-arm 2 acting upon the I-frame.

The electromagnet is connected in series of the circuit and its pawl-armature is not affected that is, not attracted by the passage of the normal current through the line; but upon the passage of an abnormal current said armature will be attracted and gripped or V This device is especially intended to prevent too rapid cutting out of the subdivisions of the resistance or rheostat, so that no matter how careless the operator may be in putting the motor into circuit a too hasty movement of the lever-arm, and, consequently, a too rapid cutting out of the sections of the resistance,

'willbe automatically prevented by the checking action of the pawl against the rack-segment and corresponding gripping of said lever-arm 2, due to the passage of a current of abnormal amperage.

It will be understood that the putting of the motor out of circuit is accomplished. in

substantially the same way-that is to say, when "the lever-arm 2 is at the extreme position to the right or left, corresponding with the engagement'of the carbon contact 13 with the corresponding contact 13, the 'full current from the line traverses the motor. If new the lever-arm is drawn back toward the normal position, the contacts 13 13, 12 12, 1111,

and 10 10" will be successively broken and a ting it into circuit, and that should too large a current traverse the line to the motor the e'lectromagnet 21 will automatically prevent the cutting outof further resistance until the normal conditions have been ire-established in the line. 7 V

I do not wish to be understood as limiting myself to the details of construction of the carbon-supporting mechanism and other mechanical portions of the switch device herein described, as they are not essential to my in:

IIO

vention and may be modified in various ways to accomplish the same result-via, the gradual and step by step making of contact through the carbon rods and the interposition and gradual cutting out thereby of sections of a divided resistancewithout departing from the spirit of the invention.

lVhile' I have shown the stationary carbon contacts as forming the terminals of the resistance-coils, the movable carbon-contacts may form the terminals, and I consider the two forms as equivalents.

I claim-- 

